This invention is related to fiber optic communications and more particularly to an optical fiber interconnection device and method for rearranging arrays of optical fibers between an input side and an output side.
The use of fiber optics for high speed communications is finding increased use within large microprocessors and multiple microprocessor systems. For example, in optical switches more and more channels are needed for transmission of data. In back planes, more optical interconnections are required as more daughter cards are added for increasing the number of channels. Cross connects may also be utilized within back planes for communicating between groups of daughter cards or microprocessors. These applications typically require that each daughter card or microprocessor be in communication with each of the other daughter cards or microprocessors in the system. These communications are achieved by connecting optical fibers in a point to point fashion between each daughter card or microprocessor and the other daughter cards or microprocessors in the system. It can therefore be appreciated that as the number of channels required is increased, the number of daughter cards or microprocessors that must communicate with each other is also increased. This creates a problem in that point to point wiring for large numbers of channels is labor intensive, costly, time consuming, and susceptible to connection errors. Additionally, because optical fibers are subject to environmental limitations such as bend radius, fiber management systems are often employed for such large systems of interconnections. Fiber management becomes a challenging problem as a number of channels and the number of point to point connections are increased resulting in higher fiber counts in the backplane.
In one known prior art system of backplane fiber optic interconnections, a single optic fiber is arranged in a desired pattern on a two-dimensional adhesive coated substrate in a controlled manner. The optic fiber is arranged to maintain a minimum bend radius in a two dimensional plane of 25 mm, which is a typical minimum to prevent damage to the fibers. After testing the single optic fiber, the substrate and optic fiber are cut at one or more locations to form an optical backplane interconnect with a desired routing pattern. However, all of the optic fibers are bonded in position requiring additional optical fiber ribbons to make the backplane connections to the printed circuit boards, creating additional optic interfaces which are subject to additional signal losses.
The present invention addresses these problems by providing an optical interconnection device whereby arrays of fibers arranged in a given orientation at an input are rearranged within the device and exit at an output arranged in a different orientation from the input. A method of accomplishing the rearrangement is to first provide a plurality of fiber arrays each containing a plurality of individual fibers. This arrangement is then fixed at an output side utilizing a suitable method such as an adhesive to form a bundle. The bundle of fibers at the output is then separated, either through an automated or manual process, in a different orientation, for example in a direction orthogonal to each fiber array at the input. Distinct ribbons or arrays are created at the output by the separating operation.
In another aspect, the present invention provides a method of creating an optical fiber interconnection in which arrays of optical fibers are provided. The matrix holding each of the arrays of optical fibers together is partially stripped or leached away at one end of the array. The stripped optical fibers are then rearranged in three-dimensional space into separate output arrays using a manual or automated process based on a desired optic fiber roadmap and bonded or adhered together to form the output arrays of the optical fiber rearrangement device.